The present invention relates to a semiconductor wafer, a semiconductor device and a process for manufacturing the semiconductor device. More particularly, the invention relates to a semiconductor wafer to be used for manufacturing a semiconductor device, which is constructed by connecting a high concentration impurity layer existing at a predetermined depth from a principal face, electrically with bump electrodes disposed on the principal face through a high concentration impurity diffusion region extending from the principal face to the high concentration impurity layer; a semiconductor device manufactured by using the semiconductor wafer; and a process for manufacturing the semiconductor device.
A semiconductor element which is constructed by forming trenches having a depth extending from the principal face to the high concentration impurity layer and filling the trenches with metal, low-resistance silicon or high impurity concentration silicon, so that a high concentration impurity layer existing at a predetermined depth from the principal face may be electrically connected with electrodes formed on the principal face is well known in the art. See JP-A-2002-353452.
A well known alternative embodiment comprises a construction which takes an electric junction between the surface and back of a wafer through a metal layer covering the side faces of through holes formed over scribing lines. See JP-A-2002-261192. Also well known in the art is a method for making wiring patterns that are formed on the two faces of a substrate, mutually conductive, by forming through holes in the substrate and by filling up the insides of the through holes with a plating metal. See JP-A-2002-141440.
If, however, the trenches or through holes are formed in a semiconductor wafer or the like, as disclosed in the above prior art embodiments, the wafers are apt to be cracked or chipped when the semiconductor wafer or the like is handled in the manufacturing process of the semiconductor device. If the trenches or through holes are filled with metal or silicon, voids are apt to be left in the trenches or through holes. Finally, if the material for filling up the trenches or through holes is a metal, the semiconductor wafer warps, because the metal and the semiconductor have different coefficients of thermal expansion.